A small concretion consisting of manganese and iron oxides, occurring in large numbers in ocean-floor sediment.
- ‘The manganese nodules in Table 1 were those collected from the sea-bed of off-shore California.’
- ‘A co-occurrence of these two species is known from only one locality, where they were collected from manganese nodules immediately above the Grimmeri Bed.’
- ‘But as Challenger approached the West Indies the crew encountered a phenomenon that dwarfed in importance even the discovery of manganese nodules.’
- ‘Crusts of iron-manganese oxides and manganese nodules occur, particularly in red clays.’
- ‘It was on this leg of the voyage that they encountered the largest field of manganese nodules they had yet chanced across.’